Greetings from San Antonio! Iâ€™m here with more than 8,000 other breast cancer researchers, clinicians, and advocates from throughout the world to hear the latest breast cancer research findings. Every year, this conference gets lots of media coverage. So, feel free to post your thoughts or question about what you are hearing and reading in your local media. In reviewing the program for the first day of the meeting, I was struck by the fact that there did not seem to be any big new findings this year. But then the first speaker Richard Peto, an epidemiologist from the University of Oxford, reminded us that not all advances in breast cancer screening and treatment have to be earth-shattering to be important.
Dr. Peto discussed the statistical methods he uses to provide overviews of specific research topics. He has been instrumental in forging the field of meta-analyses. Met-analysis combines data from small studies that were designed in a similar fashion. The idea is that by combing the studies you get greater statistical power to find moderate effects. Dr. Peto pointed out a combination of moderate gains from mammography, chemotherapy, radiation and hormone therapy have worked together so that breast cancer deaths for women ages 35-69 are only about half of what they used to be. He combined data from trials to look more closely at these gains.
A Closer Look at Radiation
Radiation therapy is currently given to women who have more than four positive nodes or big tumors. Studies have explored whether radiation would benefit women who were node negative or who had fewer than four positive nodes. Dr. Petoâ€™s analysis showed that although radiation after mastectomy in women with negative nodes decreased local recurrence, it actually increased over all mortality because the risks were higher than the benefit. So, for this group, radiation would not be advised. However, in women with 1-3 positive nodes, radiation decreased local recurrence by 16%. Furthermore, the death rate from breast cancer was decreased by 7.3 percent at 15 years, after 5 years showed a decrease in breast cancer deaths of 7.3% at 15 years. So, for this group there was a benefit. And for women with more than 4 positive nodes, there was a 22% decrease in local recurrence and a 7% decrease in death of breast cancer at 15 yearsâ€”underscoring that radiation is important for this group as well.
Benefits of Tamoxifen Are Long-Lasting
Even more interesting is the tamoxifen story. Many women worry that when they stop taking tamoxifen or an aromatase inhibitor their cancer will just take off. Well, the data show just the opposite. If you take tamoxifen for 5 years and then stop there is a continuing improvement of survival over the next five years and even the third five years and the curves are still separating. This should be encouraging to women who took tamoxifen for only five years in the past as well as the women who have taken five years of tamoxifen for prevention of breast cancer. This suggests that tamoxifen is not just stopping breast cancer from growing but curing it! It is estimated that 400,000 women are alive because of tamoxifen, an inexpensive, relatively safe drug. A talk the next day updating the ATAC trial shows a similar effect with the aromatase inhibitor, a nastrozole (brand name Arimidex).
Taxol Beats Adriamcyin
Finally, the chemotherapy data shows that taxol is better than adriamycin, whether you are ER-positive or ER-negative. Further, the benefit is directly related to the risk of recurrence, with the highest benefit in the women at highest risk.
Don Berry, biostatistics chief at MD Anderson Cancer Center, presented the meta-analysis of high dose chemotherapy with stem cell rescue, which was popular in the 1980â€™s. The analysis found that there was a modest benefit on relapse free survival and no benefit in over all survival. A number of news outlets covered this story.
Oncotype DX: Who Needs Chemo?
The next series of talks showed that some of our strongly held beliefs might have to be revamped. We have long thought that women with positive nodes need adjuvant chemotherapy. But a study completed by Genomic Health, which makes the Oncotype DX test, found that its test is also applicable to women with positive nodes. (The test, which tells women how likely they are to have a recurrence if they use hormone therapy, is currently only being used in women who are node-negative and ER-positive.) This means that even some node-positive women may not need chemotherapy! But which chemotherapy should they have? Two different presentations questioned the routine use of adriamycin. One study showed that taxol and cytoxan is a superior combination to adriamycin and cytoxan. Another study suggested adriamycin come out ahead in women who make too much of (overexpress) a protein called TOPO II. Only about 8% of breast cancers make too much TOPO II, so we may be able to limit the use of adriamycin to this group. But the real question is whether to keep doing both, as we currently do AC followed by taxol.More to comeâ€¦..